# Trazodone: veterinary dose and monograph

> Trazodone is a veterinary sedative or anaesthetic agent. Serotonin 2A antagonist / reuptake inhibitor (SARI) — atypical antidepressant repurposed for veterinary anxiolysis. Indications include pre-visit anxiety (dogs and cats); post-operative confinement (orthopaedic recovery); storm / fireworks phobia. This monograph lists 3 reference doses for dogs and cats, each with route, frequency and source.

Source: https://vetmasterji.com/drugs/trazodone · Last reviewed: 2026-10-01

## At a glance

- **Drug class:** Sedative / anaesthetic
- **Also known as:** Desyrel, Oleptro
- **Species with doses:** Dogs and Cats
- **General dose range:** 2–10 mg/kg PO q8–24h — check the species tables for the indication
- **Routes:** PO
- **Last reviewed:** 1 October 2026

## Indications

- Pre-visit anxiety (dogs and cats)
- Post-operative confinement (orthopaedic recovery)
- Storm / fireworks phobia
- Travel anxiety
- Adjunct to behaviour modification for generalised anxiety
- Hospitalisation stress in cats

## Trazodone dose by species

Doses are per administration unless stated. mg/kg doses scale with body weight; per-animal, per-quarter and infusion-rate doses are shown as the reference writes them.

### Dogs

*Trazodone doses for dogs*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Situational anxiety (pre-visit, fireworks) | 2–8 mg/kg | PO | at least 1 h before the event | — |
| Daily adjunctive anxiety therapy | 1–5 mg/kg | PO | q12h | titrate weekly |

- Situational anxiety (pre-visit, fireworks): Plumb’s p.1140 (Neilson 2010): 2–5 mg/kg about an hour before anticipated anxiety, adjusting upward as needed (max 14 mg/kg/day). Papich 5e: typical starting dose 5–8 mg/kg, given at least 1 h before the event. Trial the dose at home first.
- Daily adjunctive anxiety therapy: Plumb’s p.1140: 1 mg/kg PO q12h for 7 days, then up to 3 mg/kg q12h (Frank 2010); 1–4.8 mg/kg PO twice daily, titrated weekly (Virga 2010). Papich 5e: typical starting dose 5–8 mg/kg q12h (q8–24h). Start at half the target dose for 3 days to limit GI signs.

### Cats

*Trazodone doses for cats*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Pre-visit / hospitalisation | 50–100 mg/cat | PO | single dose 90 min pre-event | — |

- Pre-visit / hospitalisation: 50 mg/cat (single tablet) PO. Combine with gabapentin 50–100 mg for difficult cats. Papich 5e p926: 50–100 mg/cat PO, 50 mg usually sufficient; peak effect 2–2.5 h.

## Contraindications

Hypersensitivity. Concurrent MAO-I (serotonin syndrome). Severe hepatic / renal disease (reduce dose). Concurrent serotonergic drugs (SSRI, TCA, tramadol) at high cumulative doses.

## Species-specific warnings

> **Caution:** Dogs: TEST DOSE at home first — 5–10% develop paradoxical agitation. Otherwise extremely safe. 4–10 mg/kg PO 60–90 min pre-event.

> **Caution:** Cats: 50 mg/cat PO 90 min pre-visit. Combine with gabapentin 50–100 mg for difficult cats — synergistic.

## Adverse effects

- Mild sedation (intended effect)
- Ataxia at higher doses
- GI upset (vomiting, diarrhoea) — uncommon
- Paradoxical agitation in 5–10% of dogs (use lower dose or switch)
- Priapism (humans, rare in vet) — limited reports
- Hypotension (mild)
- Cats: vocalisation, salivation at higher doses

## Drug interactions

- MAO-I: CONTRAINDICATED — serotonin syndrome
- SSRI (fluoxetine, sertraline): cumulative serotonergic effect — caution
- TCA (amitriptyline, clomipramine): additive serotonergic effect
- Tramadol: serotonin syndrome risk at high cumulative doses
- CYP3A4 inhibitors (ketoconazole, ciprofloxacin): increase trazodone levels
- CYP3A4 inducers (phenobarbital): decrease trazodone levels
- CNS depressants: additive sedation
- Antihypertensives: additive hypotension

## Pregnancy and lactation

Crosses placenta. FDA Category C (human). Limited vet data. Avoid in pregnancy unless clinically essential.

## Monitoring

- Sedation depth — test dose at home before relying on for event
- Paradoxical agitation — switch to alternative if observed
- Concurrent SSRI / TCA — serotonin syndrome risk
- Hypotension in cardiac / hypovolaemic patients
- Cats: vocalisation / hypersalivation at high doses

## Toxicity and overdose

Wide therapeutic margin. Overdose: profound sedation, hypotension, ataxia. Serotonin syndrome unlikely without co-administered serotonergic drugs. Priapism reported in human males (very rare in dogs). Cats: hyper-salivation, vocalisation, occasional aggression at high doses.

Management: Supportive — most overdoses self-limiting. Activated charcoal if recent ingestion. IV fluids for hypotension. Serotonin syndrome: cyproheptadine 1.1 mg/kg PO q6h, active cooling. Most patients recover within 12–24 h.

## Clinical pearls

- Dogs pre-visit: 4–10 mg/kg PO 60–90 min before vet visit — test dose at home first
- Dogs post-op confinement: 2–5 mg/kg PO q8–12h × 7–14 days for kennel rest after orthopaedic surgery
- Cats pre-visit: 50 mg/cat PO 90 min before transport — combine with gabapentin 50–100 mg for extra effect
- Combine with gabapentin for synergistic anxiolysis — common protocol: trazodone + gabapentin 1.5 h pre-visit
- Lower doses give anxiolysis without sedation; higher doses give frank sedation — titrate to need
- Paradoxical agitation in ~5–10% of dogs — switch to gabapentin or alprazolam alternative
- Avoid with fluoxetine + tramadol — serotonin syndrome risk
- Replaces acepromazine in most modern vet practices — better tolerated, no Boxer / stallion issues

## Mechanism of action

Serotonin antagonist and reuptake inhibitor (SARI). Primary action: 5-HT2A receptor antagonism + serotonin reuptake inhibition (weak). Also weak alpha-1 adrenergic blockade (contributes to sedation / hypotension). Effects: anxiolysis, mild sedation, sleep modulation. Not a classical SSRI — does NOT primarily increase synaptic serotonin.

## Formulations and products

- Trazodone 50 / 100 / 150 / 300 mg tablet (human)
- Desyrel — 50 / 100 / 150 / 300 mg, Tablet (human-label)

## Storage

Tablets: 15–25 °C, dry, protected from light.

## Before you use this dose

> **Caution:** Reference doses for veterinary professionals. Confirm the dose against the product label, the patient’s condition, current guidance and local regulations before use; the attending veterinarian remains responsible for every clinical decision.

## Other sedatives and anaesthetics

- [Romifidine](https://vetmasterji.com/drugs/romifidine)
- [Sevoflurane](https://vetmasterji.com/drugs/sevoflurane)
- [Thiopental Sodium](https://vetmasterji.com/drugs/thiopental)
- [Tiletamine–Zolazepam](https://vetmasterji.com/drugs/tiletamine-zolazepam)
- [Xylazine](https://vetmasterji.com/drugs/xylazine)

## Frequently asked questions

### What is the dose of Trazodone for dogs?

Reference doses for Trazodone in dogs: 2–8 mg/kg PO at least 1 h before the event (Situational anxiety (pre-visit, fireworks)); 1–5 mg/kg PO q12h for titrate weekly (Daily adjunctive anxiety therapy). Confirm against the label and the patient before use.

### What is the dose of Trazodone for cats?

Reference doses for Trazodone in cats: 50–100 mg/cat PO single dose 90 min pre-event (Pre-visit / hospitalisation). Confirm against the label and the patient before use.

### When should Trazodone not be used?

Hypersensitivity. Concurrent MAO-I (serotonin syndrome). Severe hepatic / renal disease (reduce dose). Concurrent serotonergic drugs (SSRI, TCA, tramadol) at high cumulative doses.

### What are the side effects of Trazodone in animals?

Mild sedation (intended effect); Ataxia at higher doses; GI upset (vomiting, diarrhoea) — uncommon; Paradoxical agitation in 5–10% of dogs (use lower dose or switch); Priapism (humans, rare in vet) — limited reports; Hypotension (mild).

## Sources

- Plumb's Veterinary Drug Handbook
- AAFP 2022 Feline-Friendly Sedation Consensus
- Papich, Papich Handbook of Veterinary Drugs, 5th edition

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VetMasterJi is a clinical decision-support and education platform for veterinary professionals and students. It does not provide veterinary advice, diagnosis or treatment for specific animals. All drug doses, calculators and differentials are references that must be independently verified before clinical use; the attending registered veterinarian remains solely responsible for every clinical decision.